Standardize and unify MML parsing

[YuriSizov]

Currently there are many facilities in SiON's implementation for parsing MML strings. There is an obvious MMLParser (which, despite its name, is actually a very specific tool for the sequencer module). And there are bits in the TranslatorUtil as well.

Moreover, parsing is done using regular expressions, which is not the most efficient or versatile way to do this. I think an obvious improvement would be to have a dedicated, abstract, standard-following parser utility. It should be entirely possible to create one from scratch, but it's also likely there one already exists. Quick search yields this tinymml C library, for instance.

Should we still need to modify it or implement one ourselves, here's a good spec explanation:

• Nullsleep's MCK/MML Beginners Guide